title: The influence of the Klebsiella pneumoniae regulatory gene nifL upon the transcriptional activator protein NifA.
abstract: The influence of the Klebsiella pneumoniae nifL gene product upon the interaction of the transcriptional activator protein NifA with the nifH promoter has been examined using in vivo dimethylsulphate 'footprinting'. Binding of NifA to the upstream activator sequence (UAS) of the nifH promoter in the presence of the NifL protein was observed under nitrogen-limiting growth conditions. Growth in the presence of NH4+ or addition of NH4+ to nitrogen-limited cells diminished the interaction of NifA with the UAS when NifL was present. Repression of nif transcription by NifL may therefore involve an interaction between NifL and NifA which reduces the affinity of NifA for the UAS.
authors.affiliation: AFRC-IPSR Nitrogen Fixation Laboratory, University of Sussex, Brighton, UK.
authors.forename: E
authors.initials: E
authors.lastname: Morett
authors.forename: R
authors.initials: R
authors.lastname: Kreutzer
authors.forename: W
authors.initials: W
authors.lastname: Cannon
authors.forename: M
authors.initials: M
authors.lastname: Buck
mesh_terms: D000641:Ammonia / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D003720:Densitometry; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D007711:Klebsiella pneumoniae / Q000235:genetics* / Q000254:growth & development; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics*; D011401:Promoter Regions, Genetic; D013463:Sulfuric Acid Esters; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; C061338:NifA protein, Bacteria; D013463:Sulfuric Acid Esters; D014157:Transcription Factors; D000641:Ammonia; C007482:dimethyl sulfate